Controlling floral transition

Abstract

Plant Science For seed crops, such as maize and wheat, flowers need to develop at the right time to optimize harvest. Hormonal signals and metabolic status coordinate to set the transition from vegetative to reproductive growth. During acute nitrogen starvation, the plant flowers in a last-chance attempt to reproduce. Olas et al. studied what happens in the model plant Arabidopsis when nitrogen status is suboptimal, but not at starvation levels. MicroRNA regulators and nitrate-responsive gene promotor elements detect nitrogen status directly in the shoot apical meristem, from which flowers arise. With low nitrogen and short days, flowering depends more upon the availability of carbon in the form of sugar. With longer days, low nitrogen matters less. Thus, when faced with limited nitrogen supplies, the plant integrates photoperiod, hormonal, and metabolic signals to define the moment of flowering. New Phytol. 10.1111/nph.15812 (2019).